August 29, 2006

Stripe rust spreading in Australian wheat crop 

Isolated outbreaks of a fungal disease stripe rust found in wheat crops will spread through eastern Australia over the next two weeks, possibly cutting yields, Gordon Murray, a senior plant pathologist at the New South Wales' Department of Primary Industries, said Monday (Aug 29). 

However, he warned that spraying fungicide to control stripe rust on crops might not be worthwhile.

"The important thing for all farmers will be to ensure they properly assess both the yield potential and cost of applying a fungicide treatment now," Murray said in a statement.

Results from field trials over the past two years in New South Wales show economic responses to spraying fungicide for stripe rust were nonexistent in poorer yielding crops, even if those crops were highly susceptible to the disease, he said.

These show that positive economic responses to spraying susceptible wheat varieties did not occur until yield potential was above about 2.4 tonnes a hectare and above 3.5 tonnes a hectare for wheat varieties that are moderately susceptible to stripe rust.

The outlook for national wheat production has deteriorated in the face of dry weather in many wheat growing districts.

The government's Australian Bureau of Agricultural and Resource Economics, or Abare, forecast in mid-June national new wheat crop output at 22.8 million tonnes with crops in New South Wales forecast to average 2.0 tonnes a hectare. But analysts last week suggested national output would more likely be about 18.0 million tonnes.

Abare is scheduled to update its forecasts Sep 19.